1. Field of the Invention
The present invention relates generally to water sprinkler devices, and, more particularly, to high capacity agricultural irrigation sprinklers that travel along a field that is under irrigation.
2. Description of the Prior Art
Irrigation of crop fields is a widely employed technique in present day agriculture. U.S. Pat. No. 3,559,887 discloses a sprinkler head used in agricultural irrigation. One irrigation technique employs a sprinkler that is placed on a trolley that is pulled along a straight line down the middle of a rectangular field. The rectangular field has a length and a width; that is, the field has two length sides and two width sides. The straight line extends along the length of the field between the midpoints of the respective width sides. Thus, the straight line is a center line dividing the field into two halves. As the trolley and the sprinkler travel along the center line, the sprinkler has a rotating and oscillating portion which sprays water in a repeating, oscillating pattern that is an approximately 180 degree half circular pattern on the field. With this repeating, 180 degree half circular pattern over the entire field, some of field areas, especially in mid-field, get more water than desired. As a result, there is a tendency of water to pool and puddle in the middle portions of the field. In this respect, it would be desirable if an irrigation device for a field were provided which prevented water from pooling and puddling in middle portions of a field.
In using the trolley and sprinkler, the trolley and sprinkler are generally placed at a first width side, distal to a motorized spooler, and pulled by the motorized spooler toward the second width side, proximal to the motorized spooler. The motorized spooler spools the water hose that is connected to a water source at one end to the sprinkler at the other end. The motorized spooler is generally connected to a tractor. As the trolley and sprinkler get closer to the motorized spooler and the nearby tractor, the spray pattern from the sprinkler drenches the motorized spooler and the tractor. In this respect, it would be desirable if an irrigation device for a field were provided which did not spray the motorized spooler and the tractor when the trolley and the sprinkler are near the spooler and tractor.
The circular pattern has a radius that is approximately equal to one-half the width of the field. Therefore, as the trolley and sprinkler move down the center line, the field is wetted along its entire width in a pattern of advancing arcs.
For purposes of discussion, assume that the length of the field is L and that the width of the field is W. This means that the radius of the circular pattern provided by the sprinkler is (1/2)W. When the trolley and sprinkler reach one end of the center line at one width side of the field, the trolley and sprinkler are located at a center of a circle having a radius of (1/2)W. If the sprinkler is set to operate to rotate a full circle of 360 degrees, then the sprinkler sprays a surface area A=2(PI)(1/2)W. One half of this surface area covers the field. However, one half of this surface area is outside the field. The same situation develops when the trolley and the sprinkler reach the other end of the center line at the second width side of the field. That is, at the second width side of the field, one half of the surface area sprayed by the sprinkler located at the midpoint of the second width side of the field is outside the field.
Thus, it can be seen, that with this irrigation arrangement, taking both width sides of the field into consideration, a total surface area that is outside the field that is sprayed by the sprinkler is A=2(PI)(1/2)W. For a typical field, having a width W of approximately 850 feet, the surface area A that is outside the field is, in accordance with the above-mentioned formula is 2,670 square feet. This fact results in a large waste of water in spraying areas that are not part of the field. Waste of water can be a serious waste of a precious resource. Also waste of water can be a very expensive waste of money. More specifically, 30,000 to 40,000 gallons of water can be wasted in a single night by not falling upon the field. In this respect, it would be desirable if an irrigation device for a field were provided which reduced waste of water by not spraying surface areas that are not part of the field.
Aside from the large waste of water, the areas outside the field may not be suitable for being wetted by the sprinkler. For example, the areas outside the field may be a road or highway. The area outside the field may include a house or shed. The area outside the field may include another person's property. So it can be seen, for a number of reasons, it would be desirable if the surface area sprayed outside the area of the field could be kept at a minimum or completely eliminated.
Problems in sprinkler spraying patterns could theoretically be remedied by a person periodically traveling to the trolley and sprinkler and manually making changes in sprinkler operation. However, such a theoretical possibility is not practical. It would require a person to walk long distances along a field, and it would also subject the person to drenching spraying as the person approached the trolley and sprinkler. In this respect, it would be desirable if an irrigation device for a field were provided which changed spraying patterns of the sprinkler without requiring a person to walk long distances along a field and without subjecting the person to drenching spraying.
To prevent a person from being drenched by sprinkler spraying, one could theoretically turn off the water supply when changes to the sprinkler were made manually. However, such a theoretically possibility is not practical. It is more practical not to turn off the irrigation water supply when changes to the sprinkler spraying patterns are made.
Often an irrigation sprinkling operation is carried out at night for maximum irrigating effect. Most people sleep at night, so it would be desirable if an irrigation system could operate automatically so that the irrigation system could be used at night without being attended to by personnel.
Thus, while the foregoing body of prior art indicates it to be well known to use sprinklers in agricultural irrigation systems, the prior art described above does not teach or suggest a remotely controlled, moving sprinkler apparatus which has the following combination of desirable features: (1) reduces waste of water by not spraying surface areas that are not part of a field; (2) keeps to a minimum or completely eliminates the surface area sprayed outside the area of the field; (3) prevents water from pooling and puddling in middle portions of the field; (4) does not spray the motorized spooler and the tractor when the trolley and the sprinkler are near the spooler and tractor; (5) changes spraying patterns of the sprinkler without requiring a person to walk long distances along a field and without subjecting the person to being drenched by water from the sprinkler; (6) does not require turning off the irrigation water supply when changes to the sprinkler spraying patterns are made; and (7) permits an irrigation system to operate automatically so that the irrigation system can be used at night without being attended to by personnel. The foregoing desired characteristics are provided by the unique remotely controlled, moving sprinkler apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.